Remove specified locale translations for multi-layer time axis

[markov00]

Describe the issue
The specified set of locale translation in https://github.com/elastic/elastic-charts/blob/4070da0c1f152009cd3a62abf314f6cb9f711845/packages/charts/src/chart_types/xy_chart/axes/timeslip/locale_translations.ts is used to render the size of the current aggregation in the multilayer timesplit example.
This is not used anywhere else and probably also wrongly represents some locale definitions, like the Japanese coded as ja-JA but should be ja-JP.